Bulletin of the American Physical Society
APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session F34: Mechanical and Dynamical PropertiesIndustrial
|
Hide Abstracts |
Sponsoring Units: FIAP Chair: Peter Finkel, United States Naval Research Laboratory Room: Room 226/227 |
Tuesday, March 7, 2023 8:00AM - 8:12AM |
F34.00001: Brittle and ductile failure behaviors of single crystal silicon SYED NAYEER IQBAL, Woo Kyun Kim From photo-voltaic solar cells to semiconductor devices and nanotechnology, silicon substrate is still one of the most extensively used materials because of its abundance and excellent mechanical stability and the potential to combine sensing elements and electronics. Thus, it is imperative to understand the failure behaviors of silicon on micro/nano levels to improve the mechanical reliability of silicon-based devices. While silicon is brittle in normal conditions, experimental evidence has shown that it exhibits ductile failure accompanying plastic deformation depending on temperature, strain rate, device size, and other input parameters. However, a complete understanding of the mechanisms leading to these different failure behaviors and their relations with input parameters remain unanswered. In the present work, atomic simulations based on energy minimization are used to unveil the fundamental atomic-scale mechanisms for two competing phenomena of slip deformation and crack propagation. A single crystal silicon model with an existing crack is tested in the mode-I fracture setting, using Stillinger-Weber and modified embedded atom model potentials. The test is conducted with various orientations. The local stress distribution near the crack tip is evaluated to determine the critical stresses for slip and crack propagation, respectively. The minimum energy path connecting the normal state and the deformed state is constructed to find the energy barrier and the atomic rearrangement during the deformation. |
Tuesday, March 7, 2023 8:12AM - 8:24AM |
F34.00002: Lateral Strain Engineering of Thickness Modulated Semiconductor Nanomembranes Anjali Chaudhary, Shelley A Scott, Donald E Savage, Francesca Cavallo, Max G lagally Strain engineering in semiconductors is an effective strategy for modifying bandgaps and, in turn, electronic and optoelectronic properties. Laterally varying strain fields offer the opportunity to create complex band alignments, varying carrier mobility, and localized regions of quantum confinement. We report our results on lateral strain engineering of thickness-modulated Si nanomembranes (NMs) via mechanical stretching. The general idea is that thin regions of the Si NM accommodate more strain than thick regions under a globally applied stress. We transfer 220 nm thick Si NM to flexible polyimide host substrates and pattern thick (220 nm) and thin (60 nm) regions of 20 µm and 1mm lateral dimensions using optical lithography and etching. We mechanically stress these thickness-modulated Si NMs and experimentally quantify the amount of local strain using in-situ Raman spectroscopy. We observe a %strain of twice the value in thin region (60 nm) as compared to thick region (220 nm) of 20um *1 mm lateral dimensions. We predict how different thicknesses influence the amount of strain stored in the film and how the energy band gap changes when one goes from thick to thin regions.In summary, we create a strain mosaic at 50 micrometer or less and use in-situ Raman spectroscopy to calculate the amount of strain, up to 1.5%, developed in thick (220 nm) and thin (60 nm) regions of the NM. |
Tuesday, March 7, 2023 8:24AM - 8:36AM |
F34.00003: Effects of random vacancies on the spin-dependent thermoelectric properties of Silicene nanoribbon Luis Rosales, David Zambrano, Cesar D Nunez In thermal devices the capacity to transform heat into electricity is characterized |
Tuesday, March 7, 2023 8:36AM - 8:48AM |
F34.00004: Vanadium dioxide-sapphire metasurfaces for actively tunable surface phonon polariton resonances at mid-infrared Imtiaz Ahmad, Ivan Nekrashevich, Sundar Kunwar, Pinku Roy, Matthew Gaddy, Vladimir Kuryatkov, Ayrton A Bernussi, Aiping Chen, Myoung-Hwan Kim Vanadium dioxide (VO2), a reversible insulator-to-metal phase transition (IMT) material, provides an actively tunable platform for photonics devices because the IMT makes a drastic change in VO2 optical properties. VO2 film grows well on a sapphire substrate because of the small lattice mismatch, a good quality VO2 film on sapphire has used many photonics applications for electrically and thermally tunable plasmonic devices at near- and mid-infrared. Beyond plasmonics, recent studies show phonon polaritons are more efficient ingredients in mid-infrared photonics. VO2 film on sapphire will be an attractive platform to develop phonon polaritonic metasurfaces because sapphire supports phonon polaritons at its mid-infrared Reststrahlen band (10 - 20 microns). Here, we numerically simulate and experimentally demonstrate thermally tunable surface phonon polaritonic devices based on VO2 film on sapphire working at sapphire's Reststrahlen band. The device consists of 40 nm thick gold grating (periodicity = 900 nm, gap = 100 nm) on 100 nm thick VO2 on sapphire. The cavity resonance is observed near 770 cm-1 and shows redshifts as temperature increases. We further studied different grating periods and gaps to observe the cavity resonance tuning and its dynamic redshift by heat. |
Tuesday, March 7, 2023 8:48AM - 9:00AM |
F34.00005: Temperature dependence of the infrared dielectric function and the direct band gap of InSb from 80 to 725 K Stefan Zollner, Melissa Rivero Arias, Carlos A Armenta, Carola Emminger, Cesy M Zamarripa, Jaden R Love The temperature dependence of the complex pseudo-dielectric function of bulk InSb (100) near the direct band gap was measured with Fourier-transform infrared ellipsometry between 30 and 500 meV at temperatures from 80 to 725 K in ultrahigh vacuum. After a native oxidesurface correction, the dielectric function was fitted with a Herzinger-Johs parametric semiconductor model to determine the band gap and with a Drude term to determine the electron concentration and the mobility. We find that the band gap decreases from 230 meV at 80 K to 150 meV at 450 K, as expected from a Bose-Einstein model for electron-phonon scattering renormalization of the band gap and thermal expansion. Between 450 and 550 K, the band gap remains constant and then increases again at even higher temperatures, presumably due to a Burstein-Moss shift resulting from thermally excited electron-hole pairs. The broadening of the direct band gap increases steadily with temperature. The electron concentration (calculated from the Drude tail at low energies assuming parabolic bands with a constant electron mass of 0.014m0) increases from 2×1016 cm−3 at 300 K to 3×1017 cm−3 at 700 K, in reasonable agreement with temperature-dependent Hall measurements. The electron mobility was found to decrease from 105 cm2/Vs at 450 K to 2×104 cm2/Vs at 700 K, also in good agreement with Hall effect results. We describe a theoretical model that might be used to explain these experimental results. |
Tuesday, March 7, 2023 9:00AM - 9:12AM |
F34.00006: Study of momentum-resolved exciton and free carrier properties in monolayer WS2 Xing Zhu, David R Bacon, Vivek Pareek, Joel P Urquizo, Nicholas S Chan, Fabio Bussolotti, Kenji Watanabe, Takashi Taniguchi, Michael K Man, Julien Madéo, Kuan Eng Johnson Goh, Keshav M Dani 2D semiconductors, such as monolayer transition metal dichalcogenides (TMDCs), have drawn significant attention owing to their unique electrical and optical properties. Despite this attention, much remains to be known about the excited states of these materials in momentum space. Recently, time- and angle- resolved photoemission spectroscopy (TR-ARPES) has been successfully applied to provide a momentum space prospective of the excitonic states in WSe2 monolayer and multilayered heterostructures 1-3. Here we simultaneously access both the excitons and free carriers in monolayer WS2 across the entire first Brillouin zone. Thereby, we provide a direct measurement of the excited state properties, which critically determine the optoelectronic properties of 2D semiconductors. |
Tuesday, March 7, 2023 9:12AM - 9:24AM |
F34.00007: Probing Phonon-Dominated Transport in Sb2Se3 Thin Films Christopher Perez The need to route photonic signals and dynamically reconfigure devices for silicon photonic circuits has placed phase change Sb2Se3 at the forefront of optical materials research. This is largely due to Sb2Se3 displaying a large change in complex refractive index between crystalline and amorphous phases with no absorption losses (1-3). Surprisingly, the thermal properties of Sb2Se3 thin films are not well known, despite their technological relevance. These thermal properties play a vital role in changing phases and are critical for the optimization of emerging photonic technology. |
Tuesday, March 7, 2023 9:24AM - 9:36AM |
F34.00008: Determination of the complex optical constants of thin-film vanadium dioxide on polar dielectrics Myoung-Hwan Kim, Imtiaz Ahmad, SATYANARAYANA R KACHIRAJU, Sundar Kunwar, Pinku Roy, Matthew Gaddy, Vladimir Kuryatkov, Zach M Brown, Yejin Kwon, Ayrton A Bernussi, Aiping Chen Vanadium dioxide (VO2) has been widely used in photonics applications because the insulator-to-metal phase transition (IMT) near 67 C provides an active and reversible character to photonics devices. The device design requires precise information on the complex optical constants of VO2 across the IMT. VO2 deposited on polar dielectrics is considered a promising photonic platform hosting surface phonon polaritons at mid-/far-infrared. However, obtaining the VO2 optical constant is limited by the accessibility of an ellipsometer at infrared wavelengths. Here, we propose a useful method to extract the complex optical constants of VO2 on polar dielectrics across the IMT which relies solely on the normal incident reflection spectrum. We prepared 100 nm thick VO2 films deposited on silicon carbide and on sapphire substrates and measured the reflectance spectra at the Reststrahlen band under normal incidence at temperatures varying from 30 C to 80 C. A model combining Kramers-Kronig (KK) relations and thin film equation was used to precisely determine the changes in the spectrum during the IMT. The determined temperature-dependent complex optical constants of the VO2 films change steeply across the IMT and slight wavelength dependence of the optical constant was observed. |
Tuesday, March 7, 2023 9:36AM - 9:48AM |
F34.00009: In operando Large Electro-optical and Piezoelectric Properties Tuning Due to Domain Reconfiguration Related to Ferroelectric Phase Transitions in Relaxor Piezocrystals Peter Finkel, Samuel Lofland Electrical switching of ferroelectric domains and subsequent domain wall motion promotes strong piezoelectric activity, however, light scatters at refractive index discontinuities such as those found at domain wall boundaries. Thus, simultaneously achieving large piezoelectric effect and high optical transmissivity is generally deemed infeasible. Here, it is demonstrated that the ferroelectric domains in perovskite Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 domain-engineered crystals can be manipulated by electrical field and mechanical stress to reversibly and repeatably, with small hysteresis, transform the opaque polydomain structure into a highly transparent monodomain state. This phase transitions from the as-poled polydomain rhombohedral state to a monodomain monoclinic state can be stimulated by electric field or stress. Here we show, for the first time, that domain-engineered crystals can provide broadly tunable optical properties while simultaneously realizing an extremely large piezoelectric response via a ferroelectric-to-ferroelectric phase transformation . This control of optical properties can be achieved at very low electric fields (less than 1.5 kV cm−1) and is accompanied by a large (>10,000 pm V−1) piezoelectric coefficient that is superior to linear state-of-the-art materials by a factor of three or more. The coexistence of tunable optical transmissivity and high piezoelectricity paves the way for a new class of photonic devices. |
Tuesday, March 7, 2023 9:48AM - 10:00AM |
F34.00010: Photovoltaic sum rule, polarization distribution and the band geometry behind them Aleksandr Avdoshkin, Joel E Moore The bulk photovoltaic effect (BPVE) is a second-order optical DC current in materials with broken inversion symmetry that is important in some designs of solar cells. The connection of BPVE to spontaneous polarization has been long recognized but the precise relation has only been established in special cases. In this work, we clarify this relation for general multi-band free-electronic materials. To this end, we derive explicitly gauge-invariant expressions for both the BPVE and polarization distribution that also give an advantage for numerical calculations. We then use these expressions to identify the part of the frequency averaged BPVE given by the skewness of electronic polarization and the remaining part determined by more detailed properties of band states that we also discuss.The developed theory is illustrated for a tight-binding model of a two-dimensional dichalcogenide. |
Tuesday, March 7, 2023 10:00AM - 10:12AM |
F34.00011: Optical Activity of Solids from First Principles Xiaoming Wang, Stepan S Tsirkin, Ivo Souza, Yanfa Yan Within the framework of independent particle approximation, the optical activity tensor of solids is formulated as from different contributions: the magnetic dipole, electric quadrupole, and band dispersion terms. The first two terms have similar counterparts in the theory of finite systems, while the last term is unique for crystals. The magnetic dipole and electric quadrupole transition moments are calculated with a sum-over-states formulation. We apply the formulation to calculate and analyze the optical rotation of elemental tellurium and the circular dichroism of (6,4) carbon nanotube. Decomposed optical activity into different contributions are discussed. The calculated spectra agree well with experiments. As a showcase of achiral crystals, we calculate the optical activity of wurtzite GaN. |
Tuesday, March 7, 2023 10:12AM - 10:24AM |
F34.00012: Configurable crack wall conduction in oxide nanoelectronics Youngki YEO Mobile defects in solid-state materials play a significant role in memristive switching and energy-efficient neuromorphic computation. Techniques for confining and manipulating point defects may have great promise for low-dimensional memories. Here, we report the spontaneous gathering of oxygen vacancies at strain-relaxed crack walls in SrTiO3 thin films grown on DyScO3 substrates as a result of flexoelectricity. We found that electronic conductance at the crack walls was enhanced compared to the crack-free region, by a factor of 104. A switchable asymmetric diode-like feature was also observed, and the mechanism is discussed, based on the electrical migration of oxygen vacancy donors in the background of Sr-deficient acceptors forming n+-n or n-n+ junctions. By tracing the temporal relaxations of surface potential and lattice expansion of a formed region, we determine the diffusivity of mobile defects is consistent with oxygen vacancy kinetics of SrTiO3 (1.4×10-16 cm2/s). Our finding opens a new avenue into defect-mediated crack wall nanoelectronics. |
Tuesday, March 7, 2023 10:24AM - 10:36AM |
F34.00013: Structural and Optical Characterization of Dilute Bi-doped GaN Nanowires Grown by Molecular Beam Epitaxy Ishtiaque Ahmed Navid, Yujie Liu, Emmanouil Kioupakis, Zetian Mi We have performed detailed studies of the epitaxy and characterization of dilute Bi-doped GaN nanostructures on Si substrate. During the growth, the substrate temperature is initially kept at a high temperature for nanowire formation followed by low-temperature epitaxy to promote Bi incorporation under N2-rich conditions. Scanning electron microscopy shows that lowering the GaBiN growth temperature causes gradual changes in top c-plane nanowire morphology which indicates incremental incorporation of foreign Bi atoms. Room temperature photoluminescence emission is dominated by the band-to-band transition peak of wurtzite GaN at a wavelength of ~365 nm with intensities of Bi-doped GaN nanowires considerably lower than that of the intrinsic GaN nanowires. Moreover, room temperature micro-Raman spectra show that there are additional peaks near 650 cm-1 and 729 cm-1 in the Bi-doped samples which can be attributed to Bi local vibrational mode, indicative of a small amount of Bi incorporation in the GaN lattice. Such one-dimensional nanowires permit the synthesis of dislocation-free highly mismatched alloys due to strain relaxation, allowing efficient light absorption and charge carrier extraction. As such, work is in progress to study the photo(electro)chemical properties for N≡N and C-H bond activation of such a unique nanowire alloy system. |
Tuesday, March 7, 2023 10:36AM - 10:48AM |
F34.00014: Interplay of the metal surface electronic state and non-covalent molecular bonds in synergistic molecular assembly formation on Au(111) Dave Austin, Duy Le, Sara Lois, Ane Sarasola, Lucia Vitali, Talat S Rahman Non-covalent bonds are fundamental for designing self-assembled organic structures with potentially high responsivity to mechanical, light, and thermal stimuli. We present here results of joint scanning tunneling microscopy measurements and density functional theory (DFT) calculations that reveal the interplay between synergistic interactions of multiple highly-directional bonds of a pure electrostatic nature and the metal surface states that give rise to the assembly of one molecular specie, namely 4,7-dibromobenzo[c]-1,2,5-thiadiazole (2Br-BTD), in two different patterns on Au(111). Our DFT calculations find the 2Br-BTD layer to be buckled and the molecules to be weakly adsorbed on the Au(111) surface at a distance of 3.38 Å. Interestingly, the Au(111)’s surfaces state shift by 65 meV towards the Fermi level. More importantly, despite the weak interaction between the molecular film and the surface, there is hybridization of the surface states and molecular orbitals giving rise to new partially occupied orbitals of the organic molecules. Our work indicates that despite the weak adsorption of organic molecules, the Au(111) surface impacts the electronic and geometric structure of the 2Br-BTD layer. |
Tuesday, March 7, 2023 10:48AM - 11:00AM |
F34.00015: Defect-driven pinching of hysteretic characteristics in Bi1/2Na1/2TiO3-based ferroelectric thin films Yong Jin Jo, Muhammad Sheeraz, Tran Viet-Dung, Gyehyeon Kim, Changhee Sohn, Ill Won Kim, Chang Won Ahn, Young-Han Shin, Tae Heon Kim Disorders in ferroelectric thin films highly affect local polarization switching and linked hysteresis behaviors. In this work, we demonstrate line dislocation effects on ferroelectric hysteresis in epitaxial lead-free ferroelectric Bi1/2(Na0.82K0.18)1/2TiO3 (BNKT) thin films. To accomplish this, we prepare epitaxial BNKT thin films at low and high growth temperatures using pulsed laser deposition. BNKT thin films grown at low temperatures show dominant single c-domains corresponding to a single hysteresis loop. By contrast, BNKT thin films grown at high temperatures show additional a-domains and a pinched hysteresis loop differently from a single hysteresis loop. Local BNKT lattices have A-site cation deficiency due to local Bi elements being volatile at high growth temperatures. A-site deficient BNKT lattices gain unit-cell-volume shrinkage and form a-domains through accommodating in-plane tensile strains. Theoretical results by phase-field simulation show ferroelectric 90° domain wall pinning leading to double hysteresis characteristics at defect sites with screw dislocation. More details of our work will be presented in the coming on-site conference. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700